Six Russian Sukhoi-27 fighter jets and three transport planes have been deployed at Bobruisk airfield in Belarus. Earlier this week Belarus President Aleksandr Lukashenko invited Russian forces to fend off potential NATO threat.

“In case of continuing build-up of military forces in
countries bordering Belarus, the country will take adequate
response measures,” says a statement from the country’s
Defense Ministry in Minsk.

NATO is sending 12 F-16 craft in Poland, in the wake of the
Crimea crisis, and Polish President Bronislaw Komorowski has
asked for an even greater US presence. Baltic states have also
requested military assistance from NATO.

Just like their NATO counterparts, the Russian aircraft in
Belarus will participate in a joint training exercise.

“The joint air defense system [between Russia and Belarus] is
intended to guarantee collective security in Eastern
Europe,” the Belarusian Defense Ministry said.

Russian army's chief of staff Valery Gerasimov informed chairman
of NATO's Military Committee, Knud Bartels, of the developments
in a phone conversation on Thursday evening.

According to previous military agreements, Russian and Belarusian
troops can move freely throughout both countries, though it is
unusual for them to be stationed abroad for any prolonged period
of time.

Aleksandr Lukashenko has expressed repeated concern about NATO’s
eastward expansion since his ascension to the presidency of the
9-million-strong state in 1994, and has been one of Russia's
staunchest allies.

All the same, following the emergency of a possibility of Crimea
joining Russia following a referendum on March 16, the Belarus
leader has spoken out in favor of “maintaining Ukraine’s
territorial integrity”.